Means for regulating the voltage of dynamos of variable speed and load



March 15, 1921. 1,621,452-

H. BENIT MEANS FOR REGULATING THE VOLTAGE OF DYNAMICS OF VARIABLE SPEEDAND'LOAD Filed Aug. 13/ 1925 Patented Mar. 15, 1927;

UNITED STATES PATENT OFFICE.

HENRI IBENIT, OF PARIS, FRANCE, ASSIGNOB T LA SOCIETE DITE LECLATRAGEDES VEHICULES SUB RAIL, OF PARIS, FRANCE.

MEANS EOR'REGULATING THE VOLTAGE 0F DYNAMOS OF VARIABLE SPEED AN LOAD.

Application filed August 13, 1925, Serial No. 50,060, and in FranceSeptember 20, 1924.

The present invention relates more particularly to vibrating regulatorshaving two contacts and intended for the regulation of the excitation ofdynamos with variable speed or load of the type employed in the lightingof vehicles.

Figures 1 to 6 are diagrammatic views of several embodiments of theinvention.

Inthe drawing 1 denotes the armature of the dynamo, 2 its shunt excitingwinding, 3 the resistance in series with this winding and 4 the movableblade pivoted at 0 and adapted to be moved in one direction by thespring 6 in order, through the medium of the fixed contact 7, toshort-circuit the resistance. The movable blade 4 is adapted to be movedin the other direction by an electro-magnet 5,fthe coil ofwhich isbranched to the terminals of the dynamo in order, through the medium-ofthe contact 8 and the resistance 9, to shunt the exciting winding 2.

It is also known that for the object of extending the limits ofregulation of the above device, there may be used for the resistance 3 ametal having avariable temperature coefficient, e. g. iron underconditions such that its resistance increases in very large proportionswhen the current traversing it tends to increase.

In order to increase further the extent of the limits of regulation of agiven dynamo, without producing sparks which would dainage the contactsof the regulator, there may be adopted in accordance with the inventionan arrangement such as that illustrated diagrammatically in Fig. l ofthe annexed drawing.

10 represents a resistance in parallel with the resistance 3 when theautomatic switch 11 is closed. This switch is arranged in a mannersimilar to that of a vibrating regulator and comprises a plate attractedin one direction by a spring 12 and in the other by an electro-magnet13, the coil of which is connected in shunt with the terminals of theresistance 3. Resistances 14 and 15 are dis posed in series'with thecoils of the electromagnets 5 and 13 and may be variable if desired.

The operation of the arrangement is then as follows. On starting, theswitch 11 is closed, the blade 4 of the regulator is in contact with thefixed terminal 7, and the resistances 3 and 10 in parallel are entirelyshortcircuited by the regulator. The field winding 2 may thus supply themaximum possible excitation.

When the dynamo has attained the volt age for which the vibrator isregulated, the blade 4 commences to vibrate, the current in the fieldwinding 2 commences to fall at the same time as the voltage at theterminals of the resistance 3 and 10 (which would at first be Zero)commences to increase, and the current traversing the coil 13 increasesin proportion. As soon as the latter voltage reaches a certain value,the switch 11 opens and the resistance 10 is disconnected. A suddenincrease in the value of the resistances remaining in series with thefield magnets takes place, but the regulator instantaneously makes thenecessary correction in such manner as to maintain constant the voltageat the terminals of the dynamo.

If the speed of the dynamo continues to increase or if the load varies,the regulator acts in the same manner as in the known arrangement; inarticular, for high speeds and low loads the blade 4 vibrates againstthe fixed contact 8 in such manner as to shunt more or less the fieldwinding 2.

On stoppage the inverse operations take place when'in consequence of theoperation of the blade of the vibrator, the voltage at the terminals ofthe resistance 3 has become sufiiciently low, the switch 11 isautomatically closed and the resistance 10 is put in parallel with theresistance 3. Nevertheless, in order that the switch 11 should notitself vibrate, it is necessary that there should be a snfiicientdifference between the voltage at the terminals of the electro-magnet 13which opens the switch and that which closes it.

Just as with the known arrangement, the extent of the limits ofregulation may be increased by employing for the resistance 3, andevenfor the resistance 10, a metal having a high temperatureco-efiicient.

The conditions of regulation may also be improved or modified byproviding in conjunction with the arrangement above-described certainknown devices, such as the automatic insertion of a resistance in seriesor in parallel with the coil of the electromagnet of the vibrator, (inorder to produce the effect often described as compensation) thecompoundin of this electro-magnet, etc.

The extent 0 the limits of regulation of the dynamo may be still furtherincreased by employing as indicated in Fig. 2 several auxiliaryresistances 10, 10', etc., and several switches 11, 11, etc., fortheseresistances. A necessary condition in this case is that theelectro-magnets 13, 13', etc., controllingthe switchesv should beregulated in such nuanner as to act successively and-at the desiredtime.

. Fig. 2 shows for the coils of these electromagnets 13, 13', etc.,independent circuits arranged in shunt with the terminals of theresistance 3, but these coils could quite well be arranged also inseries in a single circuit arranged in shunt with the terminals of thissame resistance 3.

Fig. 3 shows a variation of the preceding arrangement in which one-ofthe groups (resistance 10 and switch 11) is branched to the terminals ofthe field winding 2, in lieu of being branched to the terminals oftheresistance 3.

In this case the order of the operations of closing and opening theswitches 11, 11, should be determined in such manner that when the speedof the dynamo increases, the switch 11 first opens and the switch 11closes later; when the speed of the dynamo fallsthe switch 11 shouldopen first and the switch 11 close later.

In all cases there should be utilized the voltage at the terminals ofthe field winding itself to cause the operation of the switches 11, 11'etc., and it would be sufiicient to change the direction of action ofthe springs and of the elective-magnets of these switches.

As indicated in Fig. 4, it may even be advantageous to branch theelcctro-magnet 13 of the switch 11 to the terminals of the resistance 3and the electro-niagnet 13' of the switch 11 to the terminals of thefield magnets.

Fig. 5 shows another variant of the particular arrangement forming thesubject of the present invention. In this variant a resistance 16 inseries with the resistance 3, (and consequently with the field winding2) may be short-circuited or put in circuit by the automatic switch 11.The circuit of the coil 13 and of its resistance 15 is branched in shuntto the terminals of both of the resistances 3, 1G, in series with thefield winding 2.

The operation of the device in the arrangement referred to will'beeasily followed, having regard to the explanations given in connectionwith the arrangement shown in Fig. 1.

For dynamos of a certain power there may be used two or more than tworesistances 16, 16, etc., (see Fig. 6) and as many correspondingswitches 11, 11, with the double condition of exciting each of theelectro-magnets of these switches by means of a coil under the influenceof the differarrangement.

- Havin now )articularl described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is:

1. Means for regulating the voltage of dynamos of variable speed andvariable .load, with vibrating regulators having two contacts,comprising in combination with a dynamo having a field winding and aresistance in series with the field winding, a second resistancebranched in parallel with said first resistance, an eleetro-magneticautomatic switch in the connection between the second resistance and thefield winding, the magnet of said switch having its terminals connectedto the terminals of the first named resistance, whereby said magnet isunder the influence of the'difierence of potential at the terminals ofthe resistance in the field winding.

2. Means for regulating the voltage of dynamos of variable speed andvariable load, with vibrating regulators having two contacts, comprisingin combination with a dynamo having a field winding and a resistance inseries with the field winding, a second resistance branched in parallelwith said field winding, an electro-magnetic auto matic switch in theconnection between the second resistance and the field winding, themagnet of said switch having its terminals connected to the terminals ofone of the elements of the field winding, whereby said magnet is underthe influence of the difference of potential at the terminals of saidelement.

In witness whereof I have hereunto set my hand.

HENRI BENIT.

